High contrast cathode ray tube with integrated filter

Abstract

The invention concerns a novel image reproducing structure for use in a cathode ray tube. This structure comprises a glass substrate which is transmissive of visible light and has a screen supporting target surface on one side thereof and a viewing surface on the opposite side. The screen comprises a phosphor deposit which is applied to at least a portion of the target surface and responds to electron beam impingement thereon to produce a visible image of a predetermined hue. The image reproducing structure further includes filter means in the form of a stain that permeates an area of the glass substrate to form an integral part thereof and exhibits a predetermined different hue. The stain permeated area is interposed between at least a part of the phosphor deposit and the substrate viewing surface.

I claim: 
     
       1. An image reproducing structure for use in an image display device comprising: a substrate transmissive of visible light and comprising a target surface on one side thereof and a viewing surface on the opposite side;   a screen comprising a phosphor deposit applied to at least a portion of said target surface and responsive to electron beam impingement thereon for producing a visible image of predetermined hue; and   filter means, comprising a stain exhibiting a predetermined different hue permeating an area of said substrate and forming an integral part of said substrate and interposed between at least a part of said phosphor deposit and said substrate viewing surface.   
     
     
       2. A cathode ray tube display device for producing an enhanced contrast image, comprising: means for generating at least one electron beam and for directing said beam toward a target;   a substrate transmissive of visible light and comprising an inwardly directed target surface confronting said beam generating and directing means and an outwardly directed viewing surface;   a screen comprising a phosphor deposit applied to at least a portion of said target surface and responsive to impingement by said electron beam to produce a visible image of predeterminded hue;   and a filter means, comprising a stain exhibiting a predetermined different hue permeating an area of said substrate and forming an integral part of said substrate interposed between at least a part of said phosphor deposit and said substrate viewing surface for enhancing the contrast of said image produced by said phosphor deposit.   
     
     
       3. A multi-color cathode ray tube display device for producing an enhanced contrast image, comprising: means for generating a plurality of electron beams and for directing said beams toward a target;   a substrate transmissive of visible light and comprising an inwardly directed target surface confronting said beam generating and directing means and an outwardly directed viewing surface;   a screen comprising a multiplicity of sets of light emitting image elements disposed in an interleaved pattern upon said target surface,   each set of said image elements including a red phosphor deposit, a blue phosphor deposit and a green phosphor deposit,   each of said phosphor deposits responsive to impingement by an assigned one of said electron beams to produce a correspondingly colored visible image;   and filter means comprising a stain exhibiting a predetermined hue, different from that produced by any of said phosphor deposits, permeating an area of said substrate and forming an integral part of said substrate and interposed between at least the phosphor deposits of a selected like color and said viewing surface of said substrate for enhancing the contrast of said visible images produced by said phosphor deposits.   
     
     
       4. A multi-color cathode ray tube display device for producing an enhanced contrast image, comprising: means for generating a plurality of electron beams and for directing said beams toward a target;   a substrate transmissive of visible light and comprising an inwardly directed target surface confronting said beam generating and directing means and an outwardly directed viewing surface;   a screen comprising a multiplicity of sets of light emitting image elements disposed in an interleaved pattern upon said target surface and an interstitial target surface area devoid of image elements,   each set of said image elements including a red phosphor deposit, a blue phosphor deposit and a green phosphor deposit,   each set of said elements responsive to impingement by an assigned one of said electron beams to produce a correspondingly colored visible image;   and filter means comprising a stain exhibiting a predetermined hue, different from that produced by any of said phosphor deposits, permeating an area of said substrate and forming an integral part of said substrate and interposed between, at least the phosphor deposits of a selected like color and said interstitial area and said viewing surface of said substrate for enhancing the contrast of said visible images produced by said phosphor deposits.   
     
     
       5. An image reproducing structure as set forth in claim 1 in which said filter stain permeates that area of said substrate immediately beneath said viewing surface of said substrate. 
     
     
       6. An image reproducing structure as set forth in claim 1 in which said filter stain permeates that area of said substrate immediately beneath said phosphor deposit. 
     
     
       7. A monochrome cathode ray tube display device for producing an enhanced contrast image, comprising: means for generating at least one electron beam and for directing said beam toward a target;   a substrate transmissive of visible light and comprising an inwardly directed target surface confronting said beam generating and directing means and an outwardly directed viewing surface;   a screen comprising a phosphor deposit applied to said target surface and responsive to impingement by said electron beam to produce a visible image of predetermined hue;   and a filter means, comprising a stain exhibiting a predetermined different hue permeating an area beneath said viewing surface and forming an integral part of said substrate for enhancing the contrast of said image produced by said phosphor deposit.   
     
     
       8. A multi-color cathode ray tube display device as set forth in claim 3 in which said filter strain permeates that area of said substrate immediately beneath said phosphor deposits of said selected like color. 
     
     
       9. A multi-color cathode ray tube display device as set forth in claim 4 in whcih said filter stain permeates that area of said substrate immediately beneath said phosphor deposits of said selected like color and that area immediately beneath said interstitial surface area.